Regenerative retort-furnace.



No. 792,773. PATENTED JUNE 20, 1905.

v H. & J. W. HEGELER. REGENERATIVE RETORT FURNACE.

APPLICATION FILED DEO.12,1903.

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NITED STATES rammed June 20, 1905.

' PATENT OF ICE.

REGENERATIVE RETORT-FURNACE.

SPECIFICATION forming part of Letters Patent No. 792,778, dated June 20,1905.

Aunlieatieu filed December 12, 1903. Serial No, 184,86

To all whom, it may e0neern:

Be it known that we, HERMAN I'IEGELER and Jones W. HEGELER, of Lasalle,in the State of Illinois, have invented certain new and usefulImprovements in Regenerative Retort-Furnaces, of which the following isa specification.

Our invention relates to regenerative furnaces for heatingzinc-distilling retorts or other like retort-furnaces; and the object ofthe improvements is to provide means by .whieh an even and simultaneousheating of all the retorts in each section of the furnace and an evenreduction and distillation of the metal in the retorts can be attained,thus attaining economy in time required to reduce the metal, a largerrecovery of metal, and less fuel consumption and destruction of retorts,and also the construction for attaining these results.

One of the objects of recuperation or regeneration of heat in nearly allmetallurgical work is to attain the highest possible temperature. Inreduction and distillation processes in retorts, as in zine-smelting,this in tense heat is not required and is a disadvantage. To attaineconomy in fuel consumption and metal loss in smelting in retorts, it isnecessary to heat all the retorts in the furnace uniformly and not toheat any retort to a higher temperature than is required to reduce theore therein in the allotted time. The time required to reduce the ore ina retort is proportional to the difference between the internal andexternal temperatures of the retort, and the quantity of heat passingthe retort in a given time has relatively little ef fect upon thequantity of ore reduced in the retort in that time. The internaltemperature of a retort remains constant, or nearly so, while reductionand distillation are taking place. When all the ore in a retort isreduced, the retort takes the temperature of the external gases and whenso exposed may be seriously damaged. The higher the external temperaturethe more serious will be the damage done the retort and the greater thesubsequent loss of metal.

At present the Siemens regenerative retort-furnace is limited in heightto five tiers of retorts, and the upper tiers are charged with the less-refractory oxids or blue powder, as it is impossible to uniformly heatthe different tiers of retorts. The lowermost tiers of retorts aresubjected to an intense heat, with the result that the ore in them isreduced more quickly than in the upper tiers, and then either much oreis left in the upper tiers or the lower tiers thereafter are heated tothis intensely-high temperature and se riously damaged in attempting toreduce all the ore in the upper tiers, and the capacity of the furnaceis limited by all the retorts not working to the best advantage at alltimes. By our improvement control of the temperature throughout the fullheight of the furnace is attained, and the number of tiers of retorts islimited only by the draft and the practical height of furnaceconstruction.

- In the common form of regenerative retortfurnaces in which theproducts of combustion pass upward through one part of the retortchamberand downward through the opposite part among tiers of retorts arrangedin vertical rows the preheated air and combustible gases are introducedinto the base of the combustion-chamber through a series of separateflues which are arranged for air and gas alternately along the length orhorizontal extension of the furnace, connected alternately with the airand gas regenerators, and provided with ports or openings into the baseof the combustion-chamber. By this means all the gas and all the airenter for combustion at the bottom of the combustion-chamber and thereis produced at the place of combustion under the bottom tier of retortsthe temperature of the combustion of preheated elements undiluted byexcess of either gas or air. The products of the cornplete combustion asthey pass each tier of retorts are gradually cooled, and there isconsequently an uneven heating of the retorts and an uneven distillationand reduction of the metal. Not only is the metal in the lower tiers ofretorts more quickly reduced, but said retorts are injured thereafter bythe intense heat in the lower part of the combustion-chamber.

Another form of regenerative retort-furnace having a centraldivision-wall provides a series of separate air and gas flues arrangedin the same planes longitudinally of the division-wall with ports oropenings into the combustion-chamber on the opposite sides and atdifferent heights which severally admit into each side a part of the gasand part of the air in different vertical columns under the bottomtier'of retorts, a part between the bottom and second tiers, and apartbetween the second and third tiers. The effect and operation of thisconstruction are to produce under the lowermost tiers of retorts thetemperature of the combustion of preheated elements undiluted by thepresence of an excess of either gas or air, as in the previous case, buta lesser quantity of heat is produced at the several places ofcombustion in the lower part of the combustion-chamber by decreasing theamount of gas and air entering there in combustion, and an increase intemperature is produced at the upper tiers of retorts by the gas and airentering there in combustion. 111 this case the products of combustionin the lower part of the combustion-chamber in passing the differenttiers of retorts are cooled and the temperature above is increased bythe addition of gas and air there; but the products of combustion cannotby this means be again brought to the temperature existing under thebottom tier of retorts. Thus, as in the previous case, the retorts areunevenly heated, and there is an uneven. reduction and distillation ofthe metal. The lower tiers of retorts reduce the ore sooner than theupper ones and then are exposed to a detrimentally high temperature andare often melted down and deteriorate quickly, in practice the lowerretorts lasting less than half as long as the upper ones.

By our improvement we propose to introduce the entire amount of the airat the bottom of the retort-chamber under the lower tier of retorts andto have an excess of air up to the top of the combustion-chamber and tointroduce the gases separately from the air at different heights abovethe air-ports to produce the combustion progressively as required inorder to heat all the retorts simultaneously and uniformly to thetemperature required and reduce the ore in all of them at the same rate,and we attain this result by means of the construction illustrated inthe accompanying drawing, which shows a vertical cross-section of aregenerative retort furnace containing our improvement.

In the drawing the regenerators 1, 2, 3, and 41 are located under thecombustion-ch amber 5. Said chamber is of ordinary construction, beingformed of side walls having castiron frames comprising horizontal plates7, supported in the usual manner by buckstave's 8, which also supportthe arch-roof 9. Extending up within the combustion-chamber is a centraldivision-wall 10, which is provided with ledges 1]., on which the closedends of the retorts 1.2 rest, the open ends resting upon fire-claybricks supported on the horizontal plates 7 of iron. The divisionwallextends up toward the roof, and so divides the combustion-chamber intotwo compartments 13 and 14, which communicate with each other above thedivision-wall, and each compartment contains six tiers of re torts 12,arranged in vertical rows throughout the length or horizontal extensionof said compartments.

The condensers 23 are of ordinaryconstruction and connect with the openends of the retorts, and the spaces around the retorts and between thebuckstaves 8 and horizontal plates 7 are filled with clay inthe usualmanner.

The furnace is provided on one side of the lower portion of the centraldivision-wall with an air-regenerator 1 and a gas-regenerator 2 and onthe other side with a gas-regenerator 3 and an air-regenerator 4, all ofordinaryconstruction, and these regenerators lead through the regularpits to the ordinary reversingvalves, which are not shown. A series ofshort 'l'lues 15,connected with the air-regenerator 1 on one side of thefurnace, extend upwardly in one side of the central division-wall, and asimilar series of short flues 16, connected with the a irregenerator4.,extend upwardly in the other side of the said division-wall. Each ofsaid flues 15 and 16 terminates at and leads through a single large port17 into the space 18 of the lower part of the combustionchamber beneaththe lowermost tier of retorts. These flues 1 5 and 1. 6, with theirports 17, are so constructed in order to throw the entire volume of airinto the lower part of the combustion-ch amber beneath the lowermosttier of retorts. A series of other lines 19, connected with thegas-regenerator 2 on one side of the furnace, extend straight up in oneside of the central division-wall to the top thereof, and a similarseries of flues 20, connected with the gas-regenerator 3, extendstraight up in. the other side of said division-wall .to the topthereof. These are closed on top by coverplates 21, which are arrangedbelow the plugholes 22 through the arch 9, said holes being arrangeddirectly over the-flues 19 and 20 and affording access to thecover-plates for the purpose of removing them and inspecting andcleaning the flues. Each of the said flues 19 and 20 has a port aleading into the ledges on which the other tiers of retorts rest.

The ports 17 and a b are severally under or in vertical line with theretorts.

The series flues 15 and 19 are arranged in different planeslongitudinally of the retortchamber compartment 13, as are also theseveral lines 16 and 20 in the opposite compartment 14, whereby agreater number of air and gas fines is made possible in a given lengthor horizontal extension of the furnace and a better distribution of thegases and heating is thereby attained. The ports 17 and a, having acommon entrance into the combustion-chamber, afford a better mixing ofthe gases andair at that point. The flues and 16 are very short and canbe easily cleaned.

The gases by being admitted directly beneath the retorts are given atendency to be distributed entirely across the full width of thefurnace, and a uniform heating of the front and back of the retorts isattained thereby.

In operation the correct proportions of gas and air necessary forperfect combustion are admitted at the reversing-valves, and they pass,respectively, into and through the pits and fines, all in the ordinarymanner. All the air after passing through and being preheated in theregenerator enters the lower part of the combustion-chamber 13 throughthe series of fines 15 and then pass up between the retorts 12, and thegases after passing through and being preheated in the regenerator 2pass up through the series of lines 19 and enter the combustion-chamber13 through the several ports a b, which are so proportioned in. sizethat the volume or quanti ty of gas entering through the series of ports(t in being consumed will bring the resulting mixture, which contains anexcess of free oxygen until passing the uppermost of the ports I), up tothe most advantageous zincmaking temperature, an d the quantity of gasseverally entering through each of the ports I) in being consumed willconsecutively develop sufficient heat to counteract the cooling effectof each tier of retorts, and thus retain this advantageous temperaturethroughout the full height of the furnace. The con sumed gases pass overthe top of the central division-wall and down between the retorts 12 andthrough the ports 5 and a of the opposite side, to and through theregenerators on the opposite side, and thence to the reversingvalves andchimney in the ordinary manner, and when the valves are reversed, whichis done every half-hour, the air and gas pass through the furnace in theopposite direction.

The operation may be reversed in the present furnace by admitting theentire amount of gas at the bottom of the combustionchamber by means ofthe fluos 15 and 16 and gradually ad ding the air in a similar manner tothat above described for admitting the gas through the llues 19 and 20and the several ports thereof.

We do not limit ourselves to the particular construction or location ofthe short Hues and their ports, as the action would be the same if thesellues connected the upper part of one of the regenerators at otherpoints of the combustion-ehamber below the lower tier of retorts thanthe base of the central division.

The long flues need not extend the full height of the centraldivision-wall except for the special advantage specified.

By means of our improvement it is ren dered practical to keep thetemperature of the gases under the bottom tier of retorts the same asthat passing the top tier. This is accomplished by admitting the entirevolume of air to be used in. combustion beneath the bottom tier ofretorts and introducing thereto the correct amount of gas to produce theproper Zinc-making temperature and as the gases are cooled in theirpassage up between the retorts adding under each. tier of retorts theproper amount of gas to produce further combustion, and thereby maintainthis desired temperature.

It should be noted that all the air enters at the bottom, and a largerproportion of the gases enter there also, so that the greater.

proportion of the total volume of gases entering and leaving theopposite divisions of the combustionchamber does so under the bottomtier of retorts, and a better distribution of the gases and heat isthereby effected.

By means of our improvement it is rendered practical to control thetemperature throughout the full height of the furnace, the

number of tiers of retorts is not limited, the

intense heat under the bottom tier of retorts is obviated, and thedanger of damaging them or melting them down eliminated, there is abetter distribution of the heat longitudinally and transversely, as wellas vertically, and all flues can be conveniently inspected and cleaned.The construction of our furnace is differentiated from all others inthat it has a regenerator under each compartment of the retort-chamberconnected by a series of Ilues, which have ports communicating with thespace of each compartment only beneath the lowermost tier of retortstherein, and another regenerator under each comp artment of theretort-chamber connected with the space of each compartment by a seriesof other llues, which have several ports at different heightscommunicating with the space beneath the lowermost and other tiers ofretorts, whereby all the air or gas for the entire combustion throughoutthe furnace is introduced directly and only beneath the lowermost tierof retorts, while the other element of combustion is introduced beneaththe lowermost tier of retorts and at other places above between theseveral tiers of retorts, in order to have a large excess of gas or airin the lower part of the combustion-chamber to prevent the temperatureof combustion going too high, and then to produce combustionprogressively as desired by the addition of gas or air and consume thisexcess and have perfect combustion of the gases leaving the furnace.

What is claimed is 1. In a regenerative retort-furnace of the classdescribed, the combination with the two-compartment retort-chamber, thecom- I partments communicating at the top, of regenerators locatedbeneath each of said compartments, a series of lines connecting a regenerator with each compartment of the re tort-chamber and communicatingwith the space therein below the lowermost tier of re torts only, andanother series of flues connecting a regenerator with each compartmentof the retort-chamber and having several ports at different heights andcommunicating with the spaces beneath the lower and other tiers ofretorts, as and for the purpose specified.

2. In a retort heating, regenerative furnace of the class describedprovided with a retort combustion-chamber separated into compartments,communicating at the top, by a central division-wall and regeneratorsbelow said compartments, the :[lue construction comprising a series ofshort llues connecting a regenerator with the bottom of each of saidcompartments only beneath the lower tier of retorts therein and a seriesof flues extended from other of the regenerators upwardly in the centraldivision-wall and provided with several ports communicating with saidcompartments, as specified.

3. In a furnace of the class described, having a retortcombustion-chamber separated into compartments, communicating at thetop, by a central divisionwall and regenerators below said.compartments, the llue construction comprising a series of short fiuesconnecting regenerators at each side of the division-wall with thebottom of each of said compartments only beneath the lower tier ofretorts therein and a series of long fines extended from other of theregenerators upwardly in the central division-wall and provided withseveral ports communicating with said compartments, the short and thelong flues upon each side of the division-wall being arranged indifferent planes longitudinally of said compartments, as specified.

4. In a furnace of the class described, having a retortcombustion-chamber separated into compartments, communicating at thetop, by a central division-wall and regenerators below saidcompartments, the flue construction comprising a series of short finesconnecting regenerators at each side of the division-wall with thebottom of each of said compartments only beneath the lower tier ofretorts therein and a series of long fines extended from other of theregenerators upwardly in the central division-wall and pro vided withseveral ports communicating with said compartments, the short and thelong fiues upon each side of the division-wall being arranged in thesame plane transversely of said compartments, as specified.

5. In a furnace of the class described, having a retortcombustion-chamber separated into compartments, communicating at thetop, by a central division-wall and regenerators below saidcompartments, the flue construction comprising a series of short fluesconnecting regenerators at each side of the division-wall with thebottom of each of said compartments only beneath the lower tier ofretorts therein and a series of long lines extended from other of theregenerators upwardly in the central division-wall and provided withseveral ports communicating with said compartments, the ports of theshort ilues and the lowermost ports of the long flues having commonentrance into said compartments under the lower tier of retorts, asspecified.

6. In a furnace of the class described, having a retort combustionchamber separated into compartments, communicating at the top, by acentral division-wall and an outer and an inner regenerator below eachof said compartments, the flue construction com prising a series ofshort fines connecting the outer regenerators with the space in the compartments only below the lower tier of retorts therein and a series oflong flues connecting the inner regenerators with the spaces in thecompartments below each tier of retorts, as specified.

7 In a furnace of the class described, having a retortcombustion-chamber separated into compartments, communicating at thetop, by a central division-wall and regenerators below saidcompartments, the flue construction comprising a series of short linesconnecting a regenerator with the space in the compartments only belowthe lower tier of retorts therein and a series of long flues connectinga regenerator with the spaces in each compartment below each tier ofretorts, said long fiues extending to the top of the said division-wall,as specified.

8. In a furnace of the class described, having a combustion-chamberseparated into compartments, communicating at the top, by a centraldivision-wall and regenerators below said compartments, the flueconstruction comprising a series of short flues connecting a regeneratorwith. the space in each of said compartments only beneath the lower tierof retorts therein and a series of long flues connecting a regeneratorwith the spaces in each of said compartments below each tier of retortsby means of ports arranged in vertical rows in line with the verticalrows of retorts, as specified.

HERMAN .HEGELER. JULIUS W. I'IEGELER.

Witnesses:

O. DIESTERWEG, PAUL OARUS.

